This invention relates to a computer system configured to level loads and a load leveling program.
Hitherto, there have been storage systems in which a processor that handles a logical storage device is easily switched to another processor (see, for example, JP 2008-269424 A). In the storage system of JP 2008-269424 A, each host interface (I/F) unit has a management table that is used to manage which control unit handles the control of processing of inputting/outputting data to/from a storage area of a logical storage device. When a host computer makes a request to input/output data to/from a logical storage device, the host I/F unit refers to the management table to hand over the input/output request to a control unit that handles input/output processing of the logical storage device. A microprocessor of the control unit executes input/output processing as requested by the input/output request. The microprocessor of the control unit also determines whether or not the control unit that handles the processing of inputting/outputting data to/from the logical storage device is to be switched to another control unit. When determining that the control unit that handles the input/output processing is to be switched, the microprocessor of the control unit sets the management table so that another control unit that is not the one currently handling the logical storage device handles the processing of inputting/outputting data to/from the logical storage device.
JP 2008-269424 A discloses that a load balancing plan that is to switch from one control unit to another as the resource that handles the input/output processing of a logical storage device is set in the management table without being presented to an administrator. A problem of JP 2008-269424 A is that the administrator does not have a chance to check the propriety of the switching of the control unit that handles the input/output processing of the logical storage device.